1. Field
The present invention pertains to medical devices for the treatment of orthopedic injuries, and more particularly relates to a physical rehabilitation device for the treatment of a medical condition of the foot known as plantar faciitis.
2. Description of the Related Art
The plantar fascia (plantar aponeurosis) is a bowstring that connects the metatarsal heads and the medial border of the calcaneus 9 (see FIG. 2). When taut, this bowstring supports the longitudinal arch of the foot. Because of the insertion of the plantar fascia into the metatarsal heads, when the toes are dorsiflexed the plantar fascia tightens. This phenomenon is known as the Windlass effect. The Windlass effect is utilized during normal ambulation (i.e., gait). During the toe-off phase of gait the hallux (great or first toe) is extended to lock the longitudinal arch of the foot and provide a solid foundation for propulsion of the leg through the swing phase of gait. Hence, any extension of the hallux tenses the plantar fascia and locks the longitudinal arch.
The disease this device supports is described as follows. Plantar fasciitis and heel spurs are related and common ailments that involve inflammation and damage to the plantar fascia. This usually occurs as a result of repetitive trauma and cumulative micro-damage resulting in degeneration of the plantar fascia during stress of the longitudinal arch of the foot (i.e., running, dancing, ballet, martial arts, etc.). The degeneration of the plantar fascia results in heel and/or metatarsal pain during weight bearing activities.
Since the resting tone of foot flexors (i.e., plantar flexors) exceeds that of the foot extensors (i.e., dorsiflexors), the foot assumes a plantar position while at rest. This plantar positioning of the foot at night results in relaxation of the plantar fascia. Micro-damage within the plantar fascia begins to heal in a relaxed position. Since healing cannot be completed as re-tearing occurs when the plantar fascia is tensed with the first step of the day (i.e., during toe-off during the gait cycle) creating the hallmark sign of plantar fasciitis—metatarsal or heel pain with the first step in the morning. The resulting cycle of partial healing and repetitive trauma exacerbates the pain and inflammation of plantar fasciitis. Hence, allowing the plantar fascia to heal in a tensed position will result in pain relief, decreased inflammation, and repair of the micro-damage resulting from repetitive foot trauma.
Existing devices for treatment of plantar fasciitis include therapy, massage, ice, and anti-inflammatory medications. Existing splints for the treatment of plantar fasciitis secure the great toe in one place and fix the ankle at a 90 degree angle. Traditionally, plantar fasciitis has been treated with static tibiotalar dorsiflexion or static hallux dorsiflexion at night. Both of these modes of treatment tense the plantar fascia, but neither allows for increasing dynamic tension to be applied to the plantar fascia with increased ankle plantar flexion, full and complete range of motion of the second through fifth metatarsophalangeal, tibiotalar, or subtalar joints, and minimal coverage of the foot allowing for normal heat and moisture exchange. Note that current static hallux dorsiflexion splints do not allow free second through fifth metatarsophalangeal or subtalar joint motion. All of these issues become critical, because while either form of static splinting is effective, it is normally not a practical solution to plantar fasciitis.
Few patients are compliant with static night splinting rendering these treatments practically ineffective. Static splinting interferes with the ability to ambulate normally because of static restrictions placed on the mobility of the metatarsophalangeal, tibiotalar, or subtalar joints. In addition, these splints are too bulky and interfere with normal temperature or moisture exchange at the level of the foot making sleep in these splints very uncomfortable. Lastly, static splinting results in an uncomfortable burning sensation on the plantar surface of the foot as a result of a static continuous stretch placed on an already inflamed plantar fascia. Hence, the development of a low profile dynamic tension plantar fascia splint or sock is required to increase patient compliance and treat plantar fasciitis. This medical device allows for this alternative form of treatment of dynamic splinting and thus results in improved night treatment of plantar fasciitis.